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There are a number of V4 board mods, I have a late model V4 board (December last year).? Which of the mods that are out there are “critical”, for example the audio amp would be one since little audio from the board.

Thanks!

derrick

For improving spectrum compliance you want to replace L5 and L7 and replace the relays with axicoms . Those are the more critical IMO?
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-- KB1HYR --

Hi Dey,

This I think would be the starting point (from Allison's post number 53356):

The problem is if the first transistor Q71 is not biased to the half power supply
point the output are both unbalanced and the bias is wrong.? IF Q71 collector
is not at about 6V (for 12V supply) full stop.? Adjust R72 until it is.? Then adjust
the bias if needed to the complementary pair.?

This would get the first transistor in the audio amp working correctly.? Then, if needed, one could work on the push-pull pair.

73,


Mark.